explanation op plates 37. 38. 
69 
Plate 37 
Pigs. 
'■ -'Ammonites Amallheus 
2_ A (Schlotheim) . Gloucester . . Lias. 
„• • ancosus .... (Sowerby) Black Down, Devon. Green Sand. 
V. I. p. 341. Note. 
Locality. Stratum. 
Folkstone . 
Marcham . 
Geislingen 
Gros Eislingen Lias. 
Inferior Oolite. 
Oxford Clay. 
Jura limestone. 
Lias. 
Gault. 
Calcareous Grit. 
Jura limestone. 
3 A M • • • • i,^owciuy,i JJiacK Down, IJ 
• • Humphriesianus . (Sowerby) . . Sherborne 
• A.Lamberti (Sowerby) . . Oxford . . 
• ■ Planulatus .... (Schlotheim) . Franconia 
A. Bucklaodi .... (Sowerby) . . Bath . 
• A. Lautus (Sowerby) 
8. A. Catena (Sowerby) 
9- A. Varians (Zieten) . 
Striatus (Reiniclce) 
a. Exterior dorsal margin. 
b. Rack view of the shell. 
e- Transverse section of shell. 
The figures m this Plate are selected to exemplify some 
Of the various manners in which the shells of Ammonites 
are adorned and strengthened by ribs, and flutings, and 
osses. In Vol. I. p. 340, instances are mentioned of similar 
contrivances which are applied in Art to strengthen thin 
plates of metal. Workers in Glass have also adopted a 
milar expedient in their method of fortifying small wine 
Wth^ of thin glass, made flat, and portable in the pocket, 
sid flutings passing obliquely across the 
^ es of the flask, as in many of the flattened forms of 
uionite. Similar spiral flutings are introduced for the 
boH^ purpose on the surface of thin glass pocket smelling- 
imd • other glass flasks of the same kind which are 
of tK addition of bosses to the surfaces 
roc n o tottles, produces a similar double 
csuit of ornament and streno-th. 
Plate 38. V. I. p. 347. Note. 
Lia Ammonites heterophyllus, filled with 
und^* shewing in a remarkable degree the effect of the 
'i^ating course of the edges of the transverse plates 
^oath the flat sides of the outer shell. 
